The Metabolic Syndrome (MetS) is a common problem among Veterans and is associated with a greater likelihood of cardiovascular disease (CVD). The Mediterranean diet is the only popular diet that has been shown to reduce CVD event rates but the extent to which monounsaturated fatty acid (MUFA) or polyunsaturated fatty acid (PUFA) enrichment results in improvement in parameters of MetS is unresolved. Similarly, while low intensity exercise improves the CVD risk factor profile, there have been no comparative investigations comparing MUFA and PUFA enriched diets and exercise in patients with MetS that have extended beyond 1 year. Recently, the VA established the MOVE! program, a national weight management program designed to help Veterans lose weight. Using the VA promoted program, we will perform a systematic evaluation of the effects of dietary fat composition [comparison between MUFA-enriched and PUFA enriched diet] with MOVE!. We hypothesize that a MUFA-enriched diet consisting of antioxidant, lipid reducing and insulin sensitizing properties will be superior to the less palatable PUFA- enriched diet on improving cardiometabolic parameters associated with MetS. Specifically, the MUFA MOVE! program is expected to lead to greater improvements than the PUFA MOVE! program in body composition and aerobic fitness (Specific Aim 1), endothelial dependent flow mediated vasodilation and the postprandial lipid response to a meal load (Specific Aim 2) and the mechanisms (lipolytic and lipid transfer protein activity, homeostasis model assessment-estimated insulin resistance) responsible for these effects (Specific Aim 3). Collectively, these studies will advance our understanding of mechanisms underlying the differential effects of MUFA and PUFA-enriched dietary regimens on cardiometabolic health and when combined with the MOVE! program, will provide new and useful information to Veterans (and the general public) interested in optimizing their diets for CVD disease prevention and improved vascular health. PUBLIC HEALTH RELEVANCE: Potential Impact on Veterans Health Care: According to a VA news release dated February 27, 2006, of the 7.5 million veterans receiving health benefits, more than 70% are obese and 20% are diabetic, which is considerably higher compared to the general U.S. population where the prevalence of DM approximates 7%. In view of these concerns, the VA and Department of Health and Human Services (HHS) have embarked on a coordinated campaign to educate veterans and family members about the importance of attaining a healthier diet and lifestyle. In addition to dietary modification aimed at weight loss and improving biochemical and physiologic parameters of MetS, this proposal will also utilize the MOVE! program, a national weight management program designed by the VA in an effort to coordinate diet with daily walking to reduce body weight and improve cardiovascular health. Therefore, this proposal has direct relevance to the VA health care mission.